Cavalier of Night | Activated Sleeper | Yahenni, Undying Partisan

Cards

Activate
Yahenni, Undying Partisan by sacrificing
Cavalier of Night.
When
Cavalier of Night dies, it triggers, returning
Activated Sleeper from your graveyard to the battlefield as a copy of
Cavalier of Night.
When
Activated Sleeper enters the battlefield, its first triggered ability from
Cavalier of Night triggers; choose not to sacrifice a creature.
Resolve the
Yahenni, Undying Partisan ability from step 1.
Activate
Yahenni, Undying Partisan by sacrificing
Activated Sleeper.
When
Activated Sleeper dies, its last ability from
Cavalier of Night triggers, returning itself from your graveyard to the battlefield as a copy of
Cavalier of Night.
When
Activated Sleeper enters the battlefield, it triggers; choose not to sacrifice a creature.
Resolve the
Yahenni, Undying Partisan ability from step 5.
Repeat from step 5.